There are essentially two kinds of heath insurance -- Fee-for-Service and Managed Care. Although these plans differ, they both cover an array of medical, surgical and hospital expenses. Most cover prescription drugs and some also offer dental coverage.
Fee-for-Service.
These plans generally assume that the medical professional will be paid a fee for each service provided to the patient. Patients are seen by a doctor of their choice and the claim is filed by either the medical provider or the patient.
Managed Care.
More than half of all Americans have some kind of managed-care plan. Various plans work differently and can include: health maintenance organizations (HM0s), preferred provider organizations (PPOs) and point-of-service (POS) plans. These plans provide comprehensive health services to their members and offer financial incentives to patients who use the providers in the plan.
source :Insurance Information Institute, Inc